Abstract:

A disc cartridge is provided. The disc cartridge in which is housed an
optical disc includes a main cartridge body unit, rotatably housing an
optical disc, and having an aperture for a head part for exposing a part
of the optical disc to outside across the inner and outer rims of the
optical disc, and a shutter unit mounted for movement to this main
cartridge body unit for opening/closing the aperture for the head part. A
recess into which is introduced a portion of a head part of the recording
and/or reproducing apparatus is formed in continuation to the aperture
for the head part in a surface of the main cartridge body unit on which
slides a shutter unit in an area opposite to the area of movement of the
shutter unit with the aperture for the head part in-between.

Claims:

1. A disc cartridge comprising:a disc; anda main cartridge body unit
having said disc rotatably housed therein and including a recording
and/or reproducing aperture for exposing a portion of said disc to
outside across inner and outer rims of said disc; whereinthe portion of
said recording and/or reproducing aperture along the outer rim of said
main cartridge body unit is opened by being formed with a cut-out formed
in a wall of the main cartridge body unit and extending in a direction
along the thickness of said disc.

2. The disc cartridge according to claim 1 wherein said cut-out is formed
to a height at least equal to a thickness of a surface of the main
cartridge body.

3. The disc cartridge according to claim 1 wherein said cut-out is formed
so that, when a recording and/or reproducing means of a recording and/or
reproducing apparatus is introduced into said recording and/or
reproducing aperture for recording and/or reproduction in the vicinity of
the outer rim of said disc, part of said recording and/or reproducing
means is located outside of said main cartridge body unit.

4. The disc cartridge according to claim 1 wherein the inserting lateral
side of said main cartridge body unit into a recording and/or reproducing
apparatus is a substantially semicircular arcuate section, having a
center corresponding to a center of the disc housed in said main
cartridge body unit, and wherein said recording and/or reproducing
aperture is formed facing to a lateral side of said main cartridge body
unit other than said inserting lateral side arcuate in profile.

Description:

CROSS REFERENCES TO RELATED APPLICATIONS

[0001]The present application is a divisional of U.S. patent application
Ser. No. 10/528,112 filed on Mar. 16, 2005 WHICH WAS THE National Stage
of International Application No. PCT/JP2004/010516 filed on Jul. 23, 2004
and which claims priority to Japanese Patent Application Nos. 2003-281389
and 2003-281392, filed in Japan on Jul. 28, 2003, and Japanese Patent
Application Nos. 2004-140473 and 2004-140498, filed in Japan on May 10,
2004, the disclosures of which in entirety are incorporated by reference
herein.

BACKGROUND

[0002]The present invention relates to a disc cartridge having a
disc-shaped recording medium, such as an optical disc held therein, and
to a recording and/or reproducing apparatus, employing the disc cartridge
as a recording medium.

[0003]Up to now, a disc cartridge, having a disc-shaped recording medium,
such as an optical disc, rotatably housed therein, which disc cartridge
is loaded on a disc recording and/or reproducing apparatus, as the
disc-shaped recording medium is housed therein, has been in use
extensively. This sort of the disc cartridge, comprising a disc-shaped
recording medium, housed in a main cartridge body unit, can be loaded on
or unloaded from the disc recording and/or reproducing apparatus, with
the disc-shaped recording medium in a protected state.

[0004]As this sort of the disc cartridge, such a one comprising a
disc-shaped recording medium, housed for rotation in a rectangular-shaped
main cartridge body unit, is in widespread use.

[0005]Meanwhile, in a disc cartridge, attempts are being made to reduce
its size in keeping with the size of the disc-shaped recording medium,
housed therein, with a view to reducing the size of the disc recording
and/or reproducing apparatus, assuring facilitated handling of the disc
cartridge, and to reducing the cartridge material and reducing the
production cost.

[0006]With the disc cartridge, demand is also raised for increasing the
recording capacity, in addition to reducing its size. The demand for
increasing the recording capacity for the information signals may be met
by increasing the recording density and by increasing the recording area
provided on the disc-shaped recording medium.

[0007]Such a disc cartridge in which the cartridge size is reduced in
keeping with the disc-shaped recording medium housed therein is disclosed
in the Japanese Laid-Open Patent Publication H-11-353845.

[0008]With the disc cartridge, disclosed in Patent Publication 1, the size
of the disc cartridge itself is reduced by having a substantially arcuate
lateral surface, acting as an inserting end into the recording and/or
reproducing apparatus.

[0009]The disc cartridge, disclosed in the above Publication, includes a
recording and/or reproducing aperture, opened/closed by a shutter member
provided to a main cartridge body unit, having an optical disc housed
therein, and the optical disc is partially exposed to outside via this
recording and/or reproducing aperture. The information signals are
recorded and/or reproduced for the optical disc as an optical pickup of a
recording and/or reproducing head part is exposed to outside the main
cartridge body unit via this recording and/or reproducing aperture.

[0010]With the recording and/or reproducing apparatus, employing this disc
cartridge as a recording medium, the optical pickup is moved along the
radius of the optical disc, at a position spaced apart from the disc
cartridge to scan the signal recording area of the optical disc with a
light beam to record and/or reproduce the information signals. With the
recording and/or reproducing apparatus, recording and/or reproducing the
optical disc in accordance with this system, the optical pickup is moved
at a position spaced apart from the disc cartridge, and hence there are
imitations to reducing the thickness of the apparatus by reducing its
height.

[0011]Meanwhile, in disc cartridges, used up to now, inclusive of the disc
cartridge disclosed in the Japanese Laid-Open Patent Publication
H-11-353845, the recording and/or reproducing aperture for exposing the
signal recording area of the disc-shaped recording medium to outside is
formed in a plane of the main cartridge body unit. In the case of this
sort of the disc cartridge, the recording and/or reproducing head has to
be moved within the range of the recording and/or reproducing aperture
formed in the plane of the main cartridge body unit, in order to scan the
signal recording area of the disc-shaped recording medium, with the
result that the signal recording area cannot be extended efficiently up
to the outer rim of the disc-shaped recording medium.

[0012]When an optical disc, in which attempts have been made for
increasing the recording density, is used as a disc-shaped recording
medium, an optical disc, having an objective lens of a high numerical
aperture (NA), is used as a recording and/or reproducing head, for
further reducing the beam diameter of a light beam scanning the signal
recording area of the optical disc. With the use of this sort of the
optical pickup, it is necessary for the optical pickup to be at a
position close to the oprical disc and, to this end, it is necessary for
at least a portion of the optical pickup to be introduced into the disc
cartridge. If the portion of the optical pickup intrudes into the disc
cartridge, there is placed limitation to the area of possible movement of
the optical pickup, such that the signal recording area cannot
efficiently be extended up to the outer rim of the disc-shaped recording
medium.

[0013]That is, with the conventional disc cartridge, it is difficult to
enlarge the signal recording area of the disc-shaped recording medium,
arranged therein, so that it is difficult to increase the recording
capacity if the disc-shaped recording medium is to be reduced in size at
the same time.

SUMMARY

[0014]The present invention relates to a disc cartridge, having a
disc-shaped recording medium, such as an optical disc held therein, and
to a recording and/or reproducing apparatus, employing this disc
cartridge as a recording medium.

[0015]The present invention provides in an embodiment a disc cartridge
with which the recording and/or reproducing apparatus can be reduced in
thickness.

[0016]The present invention provides in an embodiment a disc cartridge
with which the recording and/or reproducing apparatus may be reduced in
thickness at the same time as the disc cartridge is reduced in size.

[0017]The present invention provides in an embodiment a disc cartridge
with which a disc housed therein may be protected reliably.

[0018]The present invention provides in an embodiment a disc cartridge
with which a shutter member for opening/closing the recording and/or
reproducing aperture formed in the main cartridge body unit may be
improved in strength to enable the reliable opening/closure of the
recording and/or reproducing aperture.

[0019]The present invention provides in an embodiment a disc cartridge
with which the recording capacity may be increased at the same time as
the disc housed therein is reduced in size.

[0020]A disc cartridge according to the present invention comprises a
disc, and a main cartridge body unit having the disc rotatably housed
therein and including a recording and/or reproducing aperture for
exposing a portion of the disc to outside across inner and outer rims of
the disc, wherein an entrance part for a head unit provided to a
recording and/or reproducing apparatus is formed in continuation to the
recording and/or reproducing aperture, for entrance of at least a portion
of the head part.

[0021]The entrance part for the head unit is an opening continuing to the
recording and/or reproducing aperture.

[0022]A lateral surface of the entrance part for the head unit is an
inclined surface for inhibiting abutment against the head part.

[0023]The disc cartridge according to the present invention further
comprises a shutter unit for opening/closing the recording and/or
reproducing aperture. The entrance part for the head unit is formed as a
recess, in continuation to the recording and/or reproducing aperture, in
a surface on which slides the shutter unit.

[0024]A bent part for closing the space produced between the shutter
member and the entrance part for the head unit when the shutter unit has
been moved to a position of closing the recording and/or reproducing
aperture is formed on one side of the shutter member of the shutter unit
closing the recording and/or reproducing aperture.

[0025]A recessed shutter slide part is formed in an area of a surface of
the main cartridge body unit, on which slides the shutter member. The
entrance part for the head unit is formed as a recess of a depth deeper
than the depth of the shutter slide part.

[0026]A recording and/or reproducing apparatus according to the present
invention comprises a disc, a main cartridge body unit having the disc
rotatably housed therein and including a recording and/or reproducing
aperture for exposing a portion of the disc to outside across inner and
outer rims of the disc, a cartridge loading unit for loading a disc
cartridge, including a recess continuing to the recording and/or
reproducing aperture, thereon, and recording and/or reproducing means for
recording and/or reproducing the information for the disc housed in the
disc cartridge. When the recording and/or reproducing means is introduced
via the recording and/or reproducing aperture for recording and/or
reproducing the information for the disc, a portion of the recording
and/or reproducing means is introduced into the recess.

[0027]The recording and/or reproducing means is composed of an objective
lens and an optical block. When the objective lens is introduced via the
recording and/or reproducing aperture for recording and/or reproducing
the information for the disc, the optical block is introduced into the
recess.

[0028]A disc cartridge according to the present invention comprises a
disc, and a main cartridge body unit having the disc rotatably housed
therein and including a recording and/or reproducing aperture for
exposing a portion of the disc to outside across inner and outer rims of
the disc. The portion of the recording and/or reproducing aperture along
the outer rim of the main cartridge body unit is opened by being formed
with a cut-out extending from the loading surface on a recording and/or
reproducing apparatus in a direction along the thickness of the disc.

[0029]The cut-out formed in the main cartridge body unit is formed so
that, when the disc cartridge is introduced into and loaded in position
on the recording and/or reproducing aperture for recording and/or
reproduction, the cut-out is of a height at least equal to a height as
from the loading surface to the recording and/or reproducing apparatus up
to a setting surface for rotation driving means for the disc.

[0030]In the present disc cartridge, the inserting lateral side of the
main cartridge body unit into the recording and/or reproducing apparatus
is a substantially semicircular arcuate section, having a center
corresponding to the center of the disc housed in the main cartridge body
unit, and a recording and/or reproducing aperture is formed facing to a
lateral side of the main cartridge body unit other than the inserting
lateral side arcuate in profile.

[0031]When the disc cartridge according to the present invention is loaded
on the recording and/or reproducing apparatus, part of the head part for
recording and/or reproducing apparatus may be located in an entrance
aperture for the head part formed in continuation to the recording and/or
reproducing aperture, with the consequence that the recording and/or
reproducing apparatus may be reduced in size.

[0032]Since one lateral side of the entrance aperture for the head part is
formed as an inclined surface section for preventing abutment against the
head part, it is possible to prevent the head part from colliding against
the rim of the entrance aperture, when the head part is being introduced
into the entrance aperture, thus assuring stable movement of the head
part such as to enable the disc to be scanned correctly by the head part.

[0033]By providing the shutter unit, adapted for closing the recording
and/or reproducing aperture, the spacing between the shutter member and
the recess may be closed by the bent part formed on one side of the
shutter member, when the shutter unit has moved to a position of closing
the recording and/or reproducing aperture, so that the recording and/or
reproducing aperture may be hermetically closed to prevent dust and dirt
from intruding via recording and/or reproducing aperture to assure
reliable protection of the disc housed in the main cartridge body unit.

[0034]Since the entrance aperture for the head part, provided to the main
cartridge body unit, is formed as a recess deeper in depth than the slide
part along which slides the shutter unit, a larger proportion of the head
part may intrude into the inside of the main cartridge body unit, with
the consequence that the recording and/or reproducing apparatus may
further be reduced in size.

[0035]With the recording and/or reproducing apparatus, according to the
present invention, in which, when the recording and/or reproducing means
is introduced into the recording and/or reproducing aperture for
recording and/or reproducing the information for the disc, part of the
recording and/or reproducing means is introduced into the recess formed
in the disc cartridge, the apparatus itself may be reduced in size.

[0036]When the disc cartridge according to the present invention is loaded
on the recording and/or reproducing apparatus, the recording and/or
reproducing head may be located via cut-out across the inner rim and the
outside of the main cartridge body unit, as a result of which the head
part may scan up to the outermost area of the disc to increase the signal
recording area as well as the recording capacity.

[0037]Additionally, when the disc cartridge according to the present
invention is loaded on the recording and/or reproducing apparatus, the
head part provided to the recording and/or reproducing apparatus may be
introduced into the inside of the main cartridge body unit, as the head
part is positioned as from the inner rim up to the outside of the main
cartridge body unit. The result is that the head part may be brought to
the proximity of the head part, such that, when an optical disc is used
as a dies, an optical pickup having a high NA (numerical aperture)
objective lens may be used as a head part, thus achieving a high
recording density of the optical disc.

[0038]With the disc cartridge according to the present invention, the
recording capacity of the disc may be increased, as the disc is reduced
in size.

[0039]Additional features and advantages are described herein, and will be
apparent from, the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

[0040]FIG. 1 is a perspective view showing a disc cartridge according to
the present invention, looking from an upper cartridge half side.

[0041]FIG. 2 is a perspective view showing a disc cartridge according to
the present invention, looking from a lower cartridge half side.

[0042]FIG. 3 is a plan view showing a disc cartridge according to the
present invention, looking from a lower cartridge half side.

[0043]FIG. 4 is a perspective view showing a shutter unit and a main
cartridge body unit carrying this shutter unit.

[0044]FIG. 5 is a side view showing the lateral side of the disc cartridge
of the present invention carrying the shutter member.

[0045]FIG. 6 is a cross-sectional view showing the state in which the
shutter member is mounted to the main cartridge body unit.

[0046]FIG. 7 is a cross-sectional view showing the state in which the
aperture for the head formed in the main cartridge body unit has been
closed by the shutter member.

[0047]FIG. 8 is a cross-sectional view showing the state in which the disc
cartridge of the present invention has been loaded on the recording
and/or reproducing apparatus.

[0048]FIG. 9 is a perspective view showing a modification of the disc
cartridge of the present invention, looking from the upper cartridge half
side.

[0049]FIG. 10 is a perspective view showing another example of a disc
cartridge of the present invention, looking from the lower cartridge half
side.

[0050]FIG. 11 is a perspective view showing still another example of a
disc cartridge of the present invention, looking from the upper cartridge
half side.

[0051]FIG. 12 is a perspective view showing the other example of a disc
cartridge of the present invention, looking from the lower cartridge half
side.

[0052]FIG. 13 is a plan view showing a further example of a disc cartridge
of the present invention, looking from the lower cartridge half side.

[0053]FIG. 14 is a perspective view showing a shutter unit and a main
cartridge body unit carrying this shutter unit.

[0054]FIG. 15 is a perspective view showing the shutter unit and a shutter
lock unit mounted on this shutter unit.

[0055]FIG. 16 is a side view showing the lateral side of the disc
cartridge, carrying the shutter unit, according to the present invention.

[0056]FIG. 17 is a cross-sectional view showing the shutter unit mounted
to the main cartridge body unit.

[0057]FIG. 18 is a plan view showing the shutter unit locked by the
shutter lock unit.

[0058]FIG. 19 is a plan view showing the shutter unit in the unlocked
state.

[0059]FIG. 20 is a plan view showing the state in which the shutter unit
is being moved in a direction of opening an aperture for a head unit.

[0060]FIG. 21 is a plan view showing the state in which the shutter unit
has been moved in a direction of opening the aperture for the head unit.

[0061]FIG. 22 is a side view of the disc cartridge showing the opened
state of the aperture for the head unit.

[0062]FIG. 23 is a perspective view showing an example of a disc drive
device employing a disc cartridge according to the present invention.

[0063]FIG. 24 is a plan view showing the state in which the disc cartridge
is being inserted with a tilt into a cartridge insertion/ejecting opening
of the disc driving unit.

[0064]FIG. 25 is a plan view showing the state in which the disc cartridge
is being inserted with a tilt in the opposite direction into a cartridge
insertion/ejecting opening of the disc driving unit.

[0065]FIG. 26 is a plan view showing the state in which the disc cartridge
has been inserted into a cartridge holder with a controlled orientation.

[0066]FIG. 27 is a plan view showing the state in which the disc cartridge
has been inserted into a cartridge holder to unlock the shutter unit.

[0067]FIG. 28 is a plan view showing the state in which the disc cartridge
has been inserted into a cartridge holder and the shutter unit has been
moved to open the recording and/or reproducing aperture.

[0068]FIG. 29 is a plan view showing the state in which the disc cartridge
has been loaded into a cartridge holder to reproduce the optical disc.

[0069]FIG. 30 is a cross-sectional side view showing the state in which an
optical pickup has been moved to the outer rim side of the optical disc
accommodated in the disc cartridge loaded on a cartridge loading section.

DETAILED DESCRIPTION

[0070]The present invention relates to a disc cartridge, having a
disc-shaped recording medium, such as an optical disc, held therein and
to a recording and/or reproducing apparatus, employing this disc
cartridge as a recording medium.

[0071]Referring now to the drawings, a disc cartridge according to the
present invention is explained in detail.

[0072]A disc cartridge 1 according to the present invention houses therein
an optical disc 2, as a disc-shaped recording medium, for rotation
therein, and includes a main cartridge body unit 5, made up by upper and
lower cartridge halves 3, 4, abutted and bonded together, as shown in
FIGS. 1 and 2. The optical disc 2 is rotatably housed within this main
cartridge body unit 5.

[0073]The disc cartridge 1 according to the present invention houses
therein the optical disc 2, on which there are recorded program data or
video data for executing e.g. a television game, and is of an extremely
small size. The present disc cartridge 1 houses therein a small-sized
optical disc 2 with a diameter on the order of, for example, 60 mm, and
is of a size that can be held in a user's palm.

[0074]Meanwhile, the optical disc 2, housed in the present disc cartridge
1, is a replay-only disc, having information signals, such as program
data, pre-recorded thereon.

[0075]The upper and lower cartridge halves 3, 4, making up a main body
unit 5, housing the disc cartridge 1, is molded from a synthetic resin
material, and upstanding peripheral wall sections 3a, 4a are formed on
the outer rim of the halves 3, 4, respectively. The upper and lower
cartridge halves 3, 4 are bonded together, with the peripheral wall
sections 3a, 4a abutting to each other, thereby forming the main
cartridge body unit 5 delimiting a disc housing section 6 therein. The
upper and lower cartridge halves 3, 4 are bonded to each other to form
the main cartridge body unit 5, by employing a welding technique, such as
an ultrasonic welding technique, to welding projections formed upright on
the abutting sides and on the sides of the upper and lower cartridge
halves 3, 4 facing each other.

[0076]The main cartridge body unit 5, forming the disc cartridge 1
according to the present invention, has its front side, as an inserting
side end of the disc cartridge 1 into the disc recording and/or
reproducing apparatus, formed as an arcuate section 7, as shown in FIGS.
1 to 3. This arcuate section 7 is formed to a semicircle of the optical
disc 2 of a radius R1 housed within the disc housing section 6 of
the main cartridge body unit 5, with the center of the disc as a center
P0 of the semicircle, as shown in FIG. 3. That is, the arcuate
section 7 is formed as a semicircle commensurate with the semicircle of
the optical disc 2 housed within the main cartridge body unit 5.

[0077]The opposite lateral sides of the main cartridge body unit 5,
consecutive to the arcuate section 7 of the main cartridge body unit 5,
are formed as sides 8, 9 parallel to each other, while the back side of
the main cartridge body unit 5, lying opposite to the arcuate section 7,
is formed as a uniformly smoothly curved section 10.

[0078]With the disc cartridge 1 of the present invention, the front side
thereof, as an inserting side surface, is a substantially semicircular
arcuate section 7 of a curvature larger than the other side, opposite
thereto, so that, when the disc cartridge is inserted in the slot-in
style via cartridge insertion/ejection opening, the direction of
insertion into the disc recording and/or reproducing apparatus can be
identified extremely readily. In particular, with the disc cartridge 1,
reduced in size so as to be held in the user's palm, the direction of
insertion can be identified by the sensual touch feeling, thus
prohibiting mistaken insertion to enable correct loading on the disc
recording and/or reproducing apparatus. Moreover, with the present disc
cartridge 1, insertion into a slot-in type disc recording and/or
reproducing apparatus may be facilitated, while positive insertion may be
assured.

[0079]Moreover, the disc cartridge 1 may be further reduced in size, in
keeping with the optical disc 2, accommodated therein, by having the
inserting end side formed as a substantially semicircular arcuate section
7, and by having the back side opposite to the arcuate section 7
similarly formed as a curved section 10. At a mid part of the lower
cartridge half 4, forming the lower surface of the main cartridge body
unit 5, there is formed a circular center opening 12 for exposing a
center hole 11 of the optical disc 2 housed in the main cartridge body
unit 5, and the ambient part thereof, to outside, as shown in FIGS. 2 and
3. Into this center opening 12 intrudes a mating engagement portion, such
as a turntable, of a disc rotating driving mechanism, provided to the
disc recording and/or reproducing apparatus on which is loaded the disc
cartridge 1.

[0080]In the lower cartridge half 4, forming the lower surface of the main
cartridge body unit 5, there is formed an aperture for the head part 13,
operating as a recording/reproducing aperture. The aperture for the head
part 13 is provided to the lateral side 8 of the main cartridge body unit
5, and is formed as a rectangular aperture sized so as to be large enough
to permit a signal recording region of the optical disc 2, accommodated
in the main cartridge body unit 5, to be exposed to outside across the
inner and outer rims of the disc. That is, the aperture for the head part
13 is formed for being opened in the linear flat lateral side 8 different
from the front side of the main cartridge body unit 5 carrying the
arcuate section 7.

[0081]A shutter unit 15 for opening/closing the aperture for the head part
13 is movably mounted to the disc cartridge 1. The shutter unit 15
includes a flat-plate-shaped shutter member 16 of a rectangular shape
large enough to close the aperture for the head part 13 and a retention
part 17 of a U-shaped cross-section formed at the proximal side of the
shutter member 16.

[0082]The shutter member 15 is formed by punching and warping a thin metal
sheet or by shaping a synthetic resin material.

[0083]The shutter unit 15 is designed so that the upper cartridge half 3
of the cartridge body unit 5 is carried by the retention part 17, so that
the shutter unit is movable in the directions indicated by arrows A and B
for opening/closing the aperture for the head part 13. That is, the
shutter unit 15 is mounted for movement on the main cartridge body unit
5, by a slide guide 18 being carried by the retention part 17, as shown
in FIG. 4. The slide guide 18 is formed by a portion of an upstanding
peripheral wall section 3a of the upper cartridge half 3.

[0084]Referring to FIG. 4, the retention part 17, provided to the shutter
unit 15, is formed with a connecting piece 21, upstanding from the
proximal end of the shutter unit 16, and a first engagement piece 22,
bent towards the shutter unit 16, is provided to the distal end of the
connecting piece 21. On both sides of the connecting piece 21, a second
engagement piece 23, bent to an L-shape, is formed at a lower position
than the first engagement piece 22. Meanwhile, the second engagement
piece 23 is bent to an L-shape so that its distal end is protruded
towards the first engagement piece 22.

[0085]The shutter unit 15 is arranged on the main cartridge body unit 5 so
that the shutter member 16 is extended over the aperture for the head
part 13, as shown in FIG. 2. At this time, the shutter unit 15 holds the
retention part 17 in a clinching fashion by the first and second
engagement pieces 22, 23, by the first engagement piece 22 of the
retention part 17 engaging in an engagement groove 24 formed in the
lateral side of the slide guide 18 and by the L-shaped second engagement
piece 23 engaging with the distal end of the slide guide 18, as shown in
FIGS. 5 and 6. The shutter unit 15, carried in this manner, is moved in
the directions indicated by arrows A and B for opening/closing the
aperture for the head part 13, by being guided by the retention part 17.

[0086]The area of the lower cartridge half 4, traversed by the shutter
member 16, is formed with a recessed shutter slide part 19. This shutter
slide part 19 is formed to a depth D1 approximately equal to a
thickness D2 of the shutter member 16 of the shutter unit 15, as
shown in FIG. 7, in order that the shutter member 16 is not protruded
from the surface of the main cartridge body unit 5, but is extended on
the surface of the main cartridge body unit 5, for flattening out the
surface of the main cartridge body unit 5.

[0087]A recess 31 is formed in the surface of the lower cartridge half 4,
on which slides the shutter unit 15 of the main cartridge body unit 5, so
that the recess continues to one side of the aperture for the head part
13. This recess 31 operates as an entrance for at least a portion of the
optical pickup forming the head part of the recording and/or reproducing
means provided to the recording and/or reproducing apparatus. This recess
is formed on the opposite side to the shutter slide unit 19 on both sides
of the aperture for the head part 13 and extends substantially the whole
length of one side of the aperture for the head part 13, as shown in
FIGS. 3 and 7.

[0088]The recess 31, into which intrudes the head part, is formed to a
depth D3 larger than the depth D1 of the shutter slide unit 19,
for increasing the amount of intrusion of the optical pickup forming the
head part of the recording and/or reproducing means provided on the
recording and/or reproducing apparatus, as will be explained
subsequently.

[0089]The lateral surface of the recess 31 continuing to the aperture for
the head part 13 is formed as an inclined surface section 32, as shown in
FIG. 5. This inclined surface section 32 serves for avoiding abutment
against a portion of the optical pickup intruding into the recess 31, for
example, a portion of the optical block forming the optical pickup.

[0090]In the disc cartridge 1 of the present invention, one side of the
shutter member 16 of the shutter unit 15, closing the aperture for the
head part 13, is formed with a bent part 34, closing the space defined
between the shutter member 16 and the recess 31, when the shutter unit 15
has moved to a position closing the aperture for the head part 13, as
shown in FIG. 7.

[0091]Thus, the shutter unit 15, used for the disc cartridge 1 according
to the present invention, is able to close the space defined between the
shutter member 16 and the recess 31, when the shutter unit 15 has been
moved to a position of closing the aperture for the head part 13, as
shown in FIG. 7. Consequently, the aperture for the head part 13 may be
sealed hermetically to prevent dust and dirt from intruding into the
inside of the main cartridge body unit 2 through the aperture for the
head part 13 to assure reliable protection of the optical disc 5
accommodated in the main cartridge body unit 2.

[0092]In the disc cartridge 1 of the present invention, a cut-out 25 is
formed in a region of the upstanding peripheral wall section 4a of the
lower cartridge half 4 facing the aperture for the head part 13, as shown
in FIGS. 2 and 4. That is, the aperture for the head part 13 serves for
exposing an area of the main cartridge body unit 5 extending from the
inner rim up to the outer rim of the main cartridge body unit 5.

[0093]When the disc cartridge 1 of the present invention, constructed as
described above, is loaded on the recording and/or reproducing apparatus,
a portion of the optical pickup 51, forming a head part for reproducing
the information signals, recorded on the optical disc 2, may be
introduced into the recess 31, as shown in FIG. 8.

[0094]Within the recording and/or reproducing apparatus, in which is
loaded the disc cartridge 1 according to the present invention, there is
provided a cartridge loading section, not shown, for loading the disc
cartridge 1 in position. Within the recording and/or reproducing
apparatus, there are provided a disc rotation driving mechanism for
rotationally driving the optical disc 2 accommodated in the disc
cartridge 1 loaded on the cartridge loading section, and an optical
pickup 51 forming the head part for scanning the signal recording area of
the optical disc 2 rotationally driven by the disc rotation driving
mechanism for reproducing the information signals. This optical pickup 51
includes an optical block 52, having enclosed therein a light source for
radiating a light beam for scanning the signal recording area of the
optical disc 2, optical components for routing the light beam, emanated
from the light source, to the optical disc 2, and a light source
converter for detecting the return light beam reflected back from the
light source for detecting data recorded on the optical disc 2, and a
bi-axial actuator 54 having an objective lens 53 for condensing the light
beam, radiated from the light source, to the signal recording surface of
the optical disc 2.

[0095]This optical pickup 51 is carried by a slide guide shaft 55 and a
guide 56, arranged parallel to each other in the recording and/or
reproducing apparatus, so as to be movable along the radius of the
optical disc 2 housed in the disc cartridge 1 loaded on the cartridge
loading unit. The optical pickup 51 is arranged at this time so that the
objective lens 53 faces the aperture for the head part 13 provided in the
disc cartridge 1 and so that the optical block 52 is placed laterally of
the aperture for the head part 13.

[0096]If, in the present recording and/or reproducing apparatus, the
optical disc 2 is to be reproduced, the objective lens 53 may intrude via
the aperture for the head part 13 into the inside of the main cartridge
body unit 5, so that part of the optical block 52 may intrude into the
recess 31 of the disc cartridge 1, as shown in FIG. 8. The result is that
the optical pickup 51 in its entirety may be caused to approach to the
disc cartridge 1, loaded on the cartridge loading unit, and hence the
apparatus in its entirety may be reduced in thickness.

[0097]The arrangement is effective in particular for a recording and/or
reproducing apparatus employing a disc cartridge 1 having housed therein
an optical disc 2 having a diameter equal to 60 mm or less. With the
small-sized disc cartridge 1, the aperture for the head part 13 is also
small-sized, such that the optical pickup 51 in its entirety cannot be
introduced into the inside of the main cartridge body unit 5. In
particular, the optical pickup 51, made up by the optical block 52 and
the bi-axial actuator 54, cannot be reduced in size further because of
its structure.

[0098]With the use of the disc cartridge 1, according to the present
invention, the optical pickup 51, which is difficult to reduce in size in
keeping with the reduction in size of the disc cartridge 1, can be caused
to approach to the disc cartridge 1 loaded on the cartridge loading
section. That is, the optical pickup 51 may be arranged as the optical
block 52 is partially intruded into the recess 31 formed in the disc
cartridge 1.

[0099]Since the optical pickup 51 may be made to approach to the disc
cartridge 1, the recording and/or reproducing apparatus, employing the
disc cartridge 1, may be reduced in thickness.

[0100]Although the above-described disc cartridge 1 is provided with the
shutter unit 15 for closing the aperture for the head part 13, the
aperture for the head part may be left in the opened state, without
providing the shutter unit.

[0101]The disc cartridge 101 not having the shutter unit is configured as
shown in FIGS. 9 and 10.

[0102]Similarly to the disc cartridge 1, a disc cartridge 101, not having
the shutter unit, includes a main cartridge body unit 5, comprising an
upper cartridge half and a lower cartridge half, abutted and connected to
each other, and the optical disc 2 is rotationally mounted in this main
cartridge body unit 5.

[0103]Referring to FIGS. 9 and 10, the forward surface, as a lateral
surface as an inserting end into the disc recording and/or reproducing
apparatus, into which the disc cartridge 101 is introduced, is formed as
an arcuate section 7, as shown in FIGS. 9 and 10.

[0104]The opposite lateral sides of the main cartridge body unit 5,
continuing to the arcuate section 7 of the main cartridge body unit 5,
are formed as lateral sides 8, 9 not parallel to each other, while the
back side thereof, opposite to the arcuate section 7, is formed as a
smoothly curved continuous curved surface 10. That is, the back surface
of the main cartridge body unit 5, is formed as a curved portion 10
having a radius larger than the radius of the semi-circular arcuate
section 7 formed on the forward side of the main cartridge body unit 5.

[0105]With this disc cartridge 101, a center opening 11 formed centrally
of the optical disc 2 housed in the main cartridge body unit 5, and a
circular center recess 12 for exposing the rim part of the center opening
11, are formed centrally of the lower cartridge half 4, as shown in FIG.
10.

[0106]In the lower cartridge half 4, an aperture for the head part 113, as
a recording and/or reproducing aperture, is formed, as shown in FIG. 10.
The aperture for the head part 113 is formed on one lateral surface 8 of
the main cartridge body unit 5, and is formed to a rectangular profile
from a position proximate to the circular center recess 12 up to the
lateral side 8. That is, the aperture for the head part 113 is formed to
a rectangular profile of a size large enough to expose a part of the
signal recording area of the optical disc 2, housed in the main cartridge
body unit 5, to be exposed to outside across the inner and outer rims of
the disc.

[0107]The lower cartridge half 4 is also provided with an entrance
aperture for the head part 131, continuing to the aperture for the head
part 113 formed in the disc cartridge 101 of the present embodiment. Into
this entrance aperture for the head part 131 may be introduced at least a
portion of the optical pickup forming the head part of the recording
and/or reproducing means provided to the recording and/or reproducing
apparatus. This entrance aperture for the head part 131 is formed in
continuation to one side of the aperture for the head part 113 towards
the arcuate section 7 operating as an inserting end into the recording
and/or reproducing apparatus of the main cartridge body unit 5. That is,
with the disc cartridge 101 of the present embodiment, the entrance
aperture for the head part 131 is formed, such as by enlarging the side
of the aperture for the head part 113 towards the arcuate section 7 of
the main cartridge body unit 5.

[0108]With this disc cartridge 101, the optical block 52, making up the
optical pickup 51, scanning the optical disc 2 of the disc recording
and/or reproducing apparatus, may be introduced into the entrance
aperture for the head part 131. The result is that the optical pickup 51
in its entirety may be brought to close to the disc cartridge 1, loaded
on the cartridge loading section of the recording and/or reproducing
apparatus, and hence the recording and/or reproducing apparatus in its
entirety may be reduced in thickness.

[0109]In this disc cartridge 101, a lateral surface of the entrance
aperture for the head part 131 is formed as an inclined surface section
132 for evading abutment against a portion of the optical pickup 51, for
example, the optical block 52 of the optical pickup 51.

[0110]In the disc cartridge 101, not having the shutter member, the
aperture for the head part may be formed as a recess, as in the disc
cartridge 1.

[0111]The disc cartridges 1, 101 are formed as having housed therein a
replay-only optical disc 2. However, the disc cartridge according to the
present invention may similarly be applied to a disc cartridge having
housed therein a recording and/or reproducing optical disc or the like
disc-shaped recording medium with similar favorable results.

[0112]It is noted that the recording and/or reproducing apparatus,
employing the disc cartridge according to the present invention, uses a
head part which differs from one sort of the disc-shaped recording medium
to another. Referring to the drawings, a disc cartridge 201 according to
a modification of the present invention is now explained.

[0113]Similarly to the above disc cartridge, the present disc cartridge
201 has housed therein e.g. an optical disc 2, as a disc-shaped recording
medium. The disc cartridge 201 includes a main cartridge body unit 5,
obtained by abutting together and combining the upper and lower halves 3,
4, as shown in FIGS. 11 and 12. The optical disc 2 is housed for rotation
in the inside of the main cartridge body unit 5.

[0114]For the following explanation, common reference numerals are used
for depicting the components used in common with the disc cartridge 1.

[0115]The disc cartridge 201 has housed therein an optical disc 2, having
recorded thereon program data or video data for playing the television
game, and is of an extremely small size.

[0116]The main cartridge body unit 5, forming the disc cartridge 201
according to the present invention, has its front side, as an inserting
side end of the disc cartridge 1 into the disc recording and/or
reproducing apparatus, formed as an arcuate section 7, as shown in FIGS.
1 to 3. This arcuate section 7 is formed to a semicircle of the optical
disc 2 of a radius R1 housed within the disc housing section 6 of
the main cartridge body unit 5, with the center of the disc as a center
P0 of the semicircle, as shown in FIG. 3. That is, the arcuate
section 7 is formed as a semicircle commensurate with the semicircle of
the optical disc 2 housed within the main cartridge body unit 5.

[0117]The opposite lateral sides of the main cartridge body unit 5,
consecutive to the arcuate section 7 of the main cartridge body unit 5,
are formed as sides 8, 9, extending parallel to each other, while the
back side of the main cartridge body unit 5, lying opposite to the
arcuate section 7, is formed as a uniformly smoothly curved section 10.

[0118]At a mid part of the lower cartridge half 4, forming the lower
surface of the main cartridge body unit 5, there is formed a circular
center opening 12 for exposing a center hole 11 of the optical disc 2
housed in the main cartridge body unit 5, and the ambient part thereof,
to outside, as shown in FIGS. 2 and 3. At a mid part of the lower
cartridge half 4, forming the lower surface of the main cartridge body
unit 5, there is formed an aperture for the head part 13, as a recording
and/or reproducing aperture, as shown in FIGS. 2 and 3. The aperture for
the head part 13, formed in one lateral surface of the main cartridge
body unit 5, is formed to a rectangular profile large enough to permit a
portion of the signal recording area of the optical disc 2 to be exposed
to outside across the inner and outer rims of the disc. That is, the
aperture for the head part 13 is formed facing the rectilinear planar
lateral surface 8 other than the forward surface of the main cartridge
body unit 5 formed with the arcuate section 7.

[0119]To the disc cartridge 201 according to the present invention, there
is mounted a shutter unit 215 configured for opening/closing the aperture
for the head part 13. The shutter unit 215 includes a rectangular
flat-plate-shaped shutter member 216 large enough to close the aperture
for the head part 13 and a retention part 217 of a U-shaped cross-section
formed towards the substrate of the shutter member 216.

[0120]The shutter unit 215 has its part towards the upper cartridge half 3
of the main cartridge body unit 5 carried by the retention part 217 and,
in this state, is carried for movement in the direction indicated by
arrows A and B in FIG. 12 for opening/closing the aperture for the head
part 13. That is, the shutter unit 215 is mounted for movement to the
main cartridge body unit 5 in such a manner that a slide guide 18, formed
by a portion of an upstanding peripheral wall section 3a of the upper
cartridge half 3, is carried by the retention part 217, as shown in FIG.
14.

[0121]The retention part 217, provided to the shutter unit 215, is formed
with a connecting piece 221, formed upright from the proximal end of the
shutter member 216, and a first engagement piece 222, bent towards the
shutter member 216, is provided to the distal end of the connecting piece
221, as shown in FIGS. 14 and 15. On both sides of the connecting piece
221, there are formed second engagement pieces 223 bent to an L shape at
a lower level than the first engagement piece 222. The distal ends of the
second engagement pieces 223 are bent to the L shape, with the distal
ends thereof protruding towards the first engagement piece 222.

[0122]This shutter unit 215 is provided to the main cartridge body unit 5,
so that the shutter member 216 extends over the aperture for the head
part 13, as shown in FIG. 12. At this time, the first engagement piece
222 provided to the retention part 217 of the shutter unit 215 is engaged
in an engagement groove 24 formed in the lateral surface of the slide
guide unit 18, while the L-shaped second engagement pieces 223 are
engaged with the distal end of the slide guide 18, whereby the shutter
unit 1215 carries the retention part 17 by clenching it between the first
and second engagement pieces 222, 223, as shown in FIGS. 16 and 17. The
shutter unit 215, thus carried, is moved in the directions of arrows A
and B in FIG. 12, for opening/closing the aperture for the head part 13
in FIG. 12, as the shutter unit is guided by the retention part 217.

[0123]In an area of the lower cartridge half 4, traversed by the shutter
member 216, there is formed a recessed shutter slide unit 19. This
shutter slide unit 19 is formed to a depth sufficient not to permit the
shutter member 216 to emerge from the upper surface of the main cartridge
body unit 5.

[0124]Referring to FIGS. 14 and 17, a cut-out 25 is formed in an area of
the upstanding peripheral wall section 4a of the lower cartridge half 4
of the disc cartridge 201 of the present invention. That is, the area of
the aperture for the head part 13 extending from the inner rim up to the
outer rim of the main cartridge body unit 5 is opened.

[0125]At least the part of the slide guide 18 of the upper cartridge half
3 facing the aperture for the head part 13 is of a height H1 not
protruded from the lower surface 2a of the optical disc 2, facing the
lower cartridge half 4, when the optical disc 2, loaded in the disc
cartridge 1 in position, as to the height, on the cartridge loading
section in the disc recording and/or reproducing apparatus, is loaded on
the turntable, as shown in FIG. 17.

[0126]With the above-described disc cartridge 201, when the shutter unit
215 is moved to open the aperture for the head part 13, the optical
pickup, as a head part for reading out the information signals recorded
on the optical disc 2, may be located in its entirety within the main
cartridge body unit 5. In addition, when the optical pickup has been
moved to a position scanning the outer rim of the optical disc 2, the
optical blocks other than an objective lens, converging the light beam,
used for scanning the signal recording area of the optical disc 2, may be
located outside the main cartridge body unit 5, as the objective lens is
located within the main cartridge body unit 5, as will be explained
subsequently.

[0127]Hence, with the disc cartridge 201 of the present invention, the
optical pickup may be located across the inner part and an outer part of
the main cartridge body unit 5, as the optical pickup is proximate to the
optical disc 2. Thus, the signal recording area may be formed up to the
outer rim of the optical disc 2, thereby increasing the recording
capacity of the optical disc 2. Moreover, since the optical pickup may be
proximate to the optical disc 2, the numerical aperture NA of the
objective lens may be larger, while the spot of the light beam condensed
on the optical disc 2 may be smaller, thereby increasing the recording
density of the information signals recorded on the optical disc 2. Since
the recording density may be improved with increase in the recording
capacity, the optical disc in need of a preset recording capacity may be
reduced in diameter. Since the optical disc 2 may be scanned as the
optical pickup is positioned for movement across the inner and outer
parts of the main cartridge body unit 5, the main cartridge body unit 5
may be reduced in size, whilst the disc recording and/or reproducing
apparatus, employing the disc cartridge 201, may also be reduced in size.

[0128]In the surface of the lower cartridge half 4 of the main cartridge
body unit 5, on which slides the shutter unit 15, there is further formed
a recess 31 in continuation to one side of the aperture for the head part
13. This recess 31 operates as an entrance for at least a portion of the
optical pickup forming the head part of the recording and/or reproducing
means, provided to the recording and/or reproducing apparatus. The recess
is positioned facing the shutter slide 19, on both sides of the aperture
for the head part 13, and is formed for extending the entire length of
one lateral side of the aperture for the head part 13, as shown in FIGS.
12 and 16.

[0129]By providing this recess 31, the part of the optical pickup, forming
the head part used for reproducing information signals recorded on the
optical disc 2 may be introduced into the recess 31 when the disc
cartridge 201 is loaded on the recording and/or reproducing apparatus.
Hence, the optical pickup may be brought into proximity of the disc
cartridge 201, so that the recording and/or reproducing apparatus may be
reduced in thickness.

[0130]In the disc cartridge 201, according to the present invention, the
shutter unit 215, opening/closing the aperture for the head part 13, is
mounted for movement along the flat lateral surface 8 of the main
cartridge body unit 5, as shown in FIGS. 11 and 12. Thus, the shutter
unit 215 is moved linearly with the retention part 217 contacting with
the planar lateral surface 8, and hence may be moved in stability.

[0131]Moreover, since the aperture for the head part 13 is formed facing
the flat lateral surface 8 of the main cartridge body unit 5, the portion
of the lower cartridge half 4 formed with the cut-out 25 is also a
rectilinear surface. Hence, even if the cut-out 25 is formed in the lower
cartridge half and the lateral surface 8 of the main cartridge body unit
5 facing outwards is opened, the aperture for the head part 13 may be
formed in its entirety to a rectangular profile and may positively be
closed by the shutter unit 215 having the rectilinear retention part 217
of a U-shaped cross-section.

[0132]The disc cartridge 1 according to the present invention is provided
with a lock unit 227 for prohibiting the movement of the shutter unit 215
when the shutter unit 215 has been moved to a position closing the
aperture for the head part 13. The lock unit 227 of the shutter unit 215
includes a lock lever 228, mounted for rotation to the shutter unit 215,
and an engagement part 229 on the main cartridge body unit 5, engaged by
this lock lever 228, as shown in FIGS. 15 and 18.

[0133]The lock lever 228 is formed as an elongated plate-shaped member,
including an upstanding thrust part 230, extending along a lateral side
edge thereof, and an upstanding engagement piece 231 on the opposite side
for engagement by the engagement part 229, as shown in FIGS. 15 and 18.
The lock lever 228 is rotationally mounted on a lock lever mounting piece
232 provided to the shutter unit 15. The lock lever mounting piece 232 is
formed for protruding laterally of the shutter member 216 from the upper
edge of the connecting piece 221 forming the slide guide 18 of the
shutter unit 215.

[0134]The lock lever 228 is rotatably mounted about a pivot 235, mounted
in turn upright on the lock lever mounting piece 232, as the center of
rotation, so that the thrust part 230 at one end thereof faces a
rectangular window 233 formed at a mid portion of the connecting piece
221, with a pivot hole 234 at a mid part of the connecting piece 221 in
engagement by the pivot 235, as shown in FIGS. 11, 16 and 18. At this
time, the engagement piece 231, provided to the opposite side of the lock
lever 228, is protruded laterally of the shutter member 216 for extending
along the lock lever mounting piece 232.

[0135]A window 233 formed in the connecting piece 221 of the shutter unit
215 is engaged by a shutter unit movement inhibiting spring, provided for
inhibiting movement of the shutter unit 215, provided to the disc
recording and/or reproducing apparatus, to which the disc cartridge 1 is
mounted.

[0136]The lock lever 228, carried by the shutter unit 215, is rotationally
biased by a rotational force energizing spring 237, coiled about the
pivot 35, in a direction shown by an arrow C in FIG. 8 for protruding the
thrust part 230 from the window 233. The rotational force energizing
spring 237 is formed by a torsion coil spring, and has one arm section
237a retained by the thrust part 230, while having the other arm section
237b retained by the inner surface of the connecting piece 221 of the
shutter unit 215, for rotationally biasing the lock lever 228 in the
direction indicated by arrow C in FIG. 8.

[0137]The rotational position of the lock lever 228 by the rotational
force energizing spring 237 is determined by abutment of the side of the
lock lever 228 carrying the thrust part 230 against the connecting piece
221.

[0138]The shutter unit 215, carrying the lock lever 228 as described
above, is mounted for movement to the main cartridge body unit 5, by
having the retention part 217 carried by the upper cartridge half 3, as
described above.

[0139]When the shutter unit 215 is at a position of closing the aperture
for the head part 213, as shown in FIGS. 16 and 18, the lock lever 228 is
rotated in the direction of arrow C in FIG. 18, under the biasing force
of the rotational force energizing spring 237, for introducing the thrust
part 230 into the window 233 formed in the connecting piece 221. At this
time, the lock lever 228 inhibits movement of the shutter unit 215, by
the engagement piece 231 at the opposite end thereof engaging with a
mating engaging part 229, provided to the main cartridge body unit 5. The
lock lever also operates for retaining the aperture for the head part 13
in a closed state by the shutter unit 216.

[0140]The mating engaging part 229 of the main cartridge body unit 5 is
provided to an area of the inner surface of the lower cartridge half 4,
outside the area of the disc housing section 6, which may be engaged by
the engagement piece 231 of the lock lever 228 when the shutter unit 215
is in the closure position. The mating engaging part 229 is formed as one
with the lower cartridge half 4. The mating engaging part 229 is formed
with an engagement recess 229a opened on one side. In this engagement
recess 229a is introduced the engagement piece 31 provided to the lock
lever 228.

[0141]When the disc cartridge 201 is introduced into the disc recording
and/or reproducing apparatus, the lock lever 228, which has locked the
shutter unit 215 in the closure position, is rotated in the direction
indicated by arrow D in FIG. 18, against the bias of the rotational force
energizing spring 237, by the thrust part 230 being thrust by the shutter
unit movement inhibiting spring intruding into engagement with the window
233 formed in the connecting piece 221. When the lock lever 228 is
rotated in the direction of the arrow D in FIG. 18, the engagement piece
231 is disengaged from the engagement recess 229a of the mating engaging
part 229, as shown in FIG. 19, for detaching the engagement piece 231
from the engagement recess 229a of the mating engaging part 229, thereby
unlocking the shutter unit 215. The shutter unit 215 may now be movable
along the direction of the arrow A in FIG. 12, that is, in a direction of
opening the aperture for the head part 13.

[0142]Meanwhile, the opening/closure of the aperture for the head part 13
is by relative movement between the main cartridge body unit 5 and the
shutter unit 215. The opening/closure of the aperture for the head part
13 will be explained in detail subsequently.

[0143]With the above-described lock unit 27 for the shutter unit, in which
the lock lever 228, locking the shutter unit 215 in the closure position,
is mounted to the shutter unit 215, movable with respect to the main
cartridge body unit 5, the lock lever may be moved in unison with the
shutter unit 215 to follow up with the opening/closure of the aperture
for the head part 13. As a result, the lock lever 228 may be placed such
that, when the shutter unit 215 is in the position of closing the
aperture for the head part 13, at least the thrust part 230 overlies the
aperture for the head part 13, thus enabling the size of the disc
cartridge 1 to be reduced. That is, in case the lock lever 228 is
provided to the main cartridge body unit 5, it should be necessary to
provide the space, in which to arrange the lock lever 228 in its
entirety, to the main cartridge body unit 5. This necessity may be
eliminated with the disc cartridge 1 of the present invention, such that
it is only sufficient to provide solely the mating engaging part 229,
engaged by a portion of the lock lever 228, on the main cartridge body
unit 5, with the consequence that the main cartridge body unit 5 may
further be reduced in size.

[0144]The disc cartridge 201, according to the present invention, may
further be provided with a shutter opening/closure unit 238 realizing the
reliable movement of the shutter unit 15 opening/closing the aperture for
the head part 13 and which positively holds the shutter unit 215 in the
position of opening or closing the aperture for the head part 13.

[0145]This shutter opening/closure unit 238 is formed using a
bi-directional energizing unit for selectively energizing the shutter
unit 215 into movement in two directions, viz. in a direction of opening
the aperture for the head part 213 and in a direction of closing the
aperture for the head part. Specifically, the bi-directional energizing
unit is formed by a torsion coil spring 239, as shown in FIG. 18. This
torsion coil spring 239, mounted between the shutter unit 215 and the
main cartridge body unit 5, is arranged at a location towards which the
shutter unit 215 is moved in the direction of opening the aperture for
the head part 13, as shown in FIG. 18. Specifically, the torsion coil
spring 239 is mounted by engaging the distal end of an arm section 239a
in an engagement opening 240 formed in the distal end of the lock lever
mounting piece 232 and by engaging a ring 241 at the distal end of the
other arm section 239b by a support pin 242 protuberantly formed on the
inner surface of the main cartridge body unit 5.

[0146]When the torsion coil spring 239 is at the position of closing the
aperture for the head part 13, the torsion coil spring 239 biases the
shutter unit 215 in the direction indicated by the arrow B in FIG. 18 for
retaining the state of closing the aperture for the head part 13. When
the disc cartridge 201 is loaded on the disc recording and/or reproducing
apparatus, and the shutter unit 215, released from the locked state by
the lock unit 227 for the shutter unit, is moved relative to the main
cartridge body unit 5 in the direction of the arrow A in FIG. 18 for
opening the aperture for the head part 13, a coil part 239c, formed
centrally of the spring in an unfixed state, is moved in the direction of
arrow A, along which is moved the shutter unit 215. When the coil part
239c of the torsion coil spring 239 is further moved along the direction
of the arrow A and is moved beyond the location of a support pin 242,
along the direction of movement of the shutter unit 15, as shown in FIG.
20, the biasing direction is reversed. On reversion of the biasing
direction, the torsion coil spring 239 biases the shutter unit 215 into
movement along the arrow A in FIG. 20. Thus, the shutter unit 215 is
moved in a direction of opening the aperture for the head part 13, to
retain the aperture for the head part 13 in the opened position, as shown
in FIGS. 21 and 22.

[0147]When the disc cartridge 201, in a state in which the shutter unit
215 retains the aperture for the head part 13 in the opened position, is
taken out from the disc recording and/or reproducing apparatus, by way of
performing the operation for ejection, the shutter unit 215 is moved
along the direction of arrow B in FIG. 20, relative to the main cartridge
body unit 5, with the center coil part 239c being similarly moved along
the direction of arrow B. When the shutter unit 215 is further moved
along the direction of arrow B, such that it surpasses the location of
the support pin 242 along the direction of movement of the shutter unit
215, the biasing direction is reversed. On reversion of the biasing
direction, the torsion coil spring 239 biases the shutter unit 215 into
movement along the arrow B in FIG. 19, such that the shutter unit 215 is
moved in the direction of closing the aperture for the head part 213,
thereby retaining the aperture for the head part in the closed state.

[0148]The shutter unit 215, biased by the torsion coil spring 239, forming
the bi-directional energizing unit, is carried in the position of closing
the aperture for the head part 13 or in the position of opening the
aperture for the head part 13, under the biasing force of the torsion
coil spring 239, and hence may be maintained reliably in the position of
closing or opening the aperture for the head part 13.

[0149]In the disc cartridge 201, according to the present invention,
provided not only with the lock unit 227 for the shutter unit, locking
the shutter unit 215 in the closed position, but also with the shutter
opening/closure unit 238, having the bi-directional energizing unit for
selectively biasing the shutter unit 215 in the two directions, the
shutter unit 215 may be reliably retained in the position of closing the
aperture for the head part 13, while the reliable opening/closure
operation for the aperture for the head part 13 may be achieved.

[0150]For reliably closing the aperture for the head part 13, it is only
sufficient to provide the lock unit 227 for the shutter unit. For
realizing a stable opening/closure movement of the shutter unit 215,
maintaining the closed state of the aperture for the head part 13, and
for reliably maintaining the opened state of the aperture for the head
part 13, it is possible to provide only the shutter opening/closure unit
238 having the bi-directional energizing unit.

[0151]In the disc cartridge 201, according to the present invention, the
lateral surface 8 of the main cartridge body unit 5, carrying the shutter
unit 215, is formed with a guide groove 49, into which intrudes a shutter
unit releasing piece, provided to the disc recording and/or reproducing
apparatus, as shown in FIGS. 11, 16 and 22.

[0152]In the lower surface of the main cartridge body unit 5, on both
sides of the back surface thereof, forming the curved section 10, there
are formed first and second positioning holes 43, 44, engaged by
positioning pins, provided to the disc recording and/or reproducing
apparatus, as shown in FIGS. 12 and 13. Meanwhile, the second positioning
hole 44 is formed as an elongated hole, having the width-wise direction,
lying at right angles to the direction of movement of the shutter unit
15, as a long radius.

[0153]On both lateral sides 8, 9 of the arcuate section 7 of the main
cartridge body unit 5, there are provided engagement recesses 45, 46,
engaged by a portion of a cartridge loading unit, provided to the
recording and/or reproducing apparatus for loading the disc cartridge 201
thereon, as shown in FIGS. 11 and 12.

[0154]In a location proximate to the opposite lateral side 9 of the
arcuate section 7 of the main cartridge body unit 5, there is provided an
engagement recess 47 for ejection, engaged by a portion of an ejection
unit provided to the recording and/or reproducing apparatus, as shown in
FIG. 12.

[0155]In the lateral sides 8, 9 or in the bottom surface of the cartridge
main body unit 5, a discriminating opening or a discriminating recess for
identifying the sort of the optical disc 2 is provided as necessary.

[0156]An embodiment of the disc recording and/or reproducing apparatus,
employing the disc cartridge 201, according to the present invention, is
hereinafter explained.

[0157]In the disc cartridge 201, according to the present invention, there
is housed the optical disc 2, having recorded thereon the program data or
video data needed for executing e.g. a TV game. The disc recording and/or
reproducing apparatus, employing the disc cartridge 201 of the present
invention, housing this sort of the optical disc 2, is made up by a main
body unit of the apparatus 251, carrying the disc cartridge 1, and having
enclosed therein a disc driving unit for reproducing at least data
recorded on the optical disc 2, and by a display 252 for demonstrating
image data or text data reproduced from the optical disc 2, as shown in
FIG. 23.

[0158]Within the main body unit of the apparatus 251 of a disc driving
device 250, having enclosed therein the disc driving unit, shown in FIG.
23, there is provided a cartridge loading unit, not shown, including a
cartridge holder for loading the disc cartridge 201 thereon. In the front
surface, forming one of the lateral sides of the main body unit of the
apparatus 251, there is formed a cartridge inserting/ejecting opening 253
for inserting the disc cartridge 201 into a cartridge holder and for
ejecting the disc cartridge 201 loaded in the cartridge holder. The
cartridge inserting/ejecting opening 253 is formed as an opening just
large enough to permit insertion/removal of the disc cartridge 201, and
has a width W2 and a height H2 slightly larger than the width
W1 and a thickness D1, respectively, of the disc cartridge 201
inserted therein. Within the main body unit of the apparatus 251, there
is arranged a cartridge holder 254 facing the cartridge
inserting/ejecting opening 253.

[0159]On one side of the front surface of the main body unit of the
apparatus 251, there is mounted an ejection button 255 for ejecting the
disc cartridge 201 held by the cartridge holder 254.

[0160]On one side of the upper surface of the main body unit of the
apparatus 251, there are provided actuating buttons 256, 257 of a control
switch, used for carrying out e.g. a TV game. On the other side thereof,
a control key 258 for scrolling the image demonstrated on the display
252. There is also provided a loudspeaker 259 for radiating audio signals
reproduced from the optical disc 2.

[0161]Although not shown, a control bobbin for e.g. a reproducing button,
for controlling the disc driving unit, and an actuating button for a
power supply switch, are provided to the main body unit of the apparatus
251.

[0162]The display 252 is provided on the back side, opposite to the front
side, carrying the cartridge inserting/ejecting opening 253 of the main
body unit of the apparatus 251, for swinging relative to the main body
unit of the apparatus 251 via a hinge unit 260. The display 252 may be
swung towards the main body unit of the apparatus 251 so as to be
superposed on the upper surface thereof. The display 252 is formed by a
liquid crystal display panel.

[0163]The state in which the disc cartridge 201 according to the present
invention is loaded on the disc driving unit 250, constructed as
described above, is hereinafter explained.

[0164]For loading the disc cartridge 201 on the disc driving device 250,
the disc cartridge 201 is inserted via the cartridge inserting/ejecting
opening 253 into the main body unit of the apparatus 51, with the arcuate
section 10 as the inserting side, so as to be held on the cartridge
holder 254, as shown in FIG. 23.

[0165]Meanwhile, with the disc cartridge 201 according to the present
invention, the inserting end thereof via the cartridge inserting/ejecting
opening 253 is formed as the approximately semicircular arcuate section
7, so that, even when the disc cartridge 1 is inserted with a centerline
P2 along the widthwise direction of the disc cartridge significantly
inclined with respect to the centerline P1 along the width-wise
direction of the cartridge inserting/ejecting opening 253, the disc
cartridge can be smoothly inserted into the cartridge inserting/ejecting
opening 253 and reliably held by the cartridge holder 254.

[0166]That is, the disc cartridge 201, having the inserting end formed as
the approximately semicircular arcuate section 7, may be inserted into
the main body unit of the apparatus 251 at the approximately semicircular
arcuate section 7, even in case the disc cartridge is inserted via the
cartridge inserting/ejecting opening 253 with the width-wise centerline
P2 inclined by an angle up to approximately 45° towards left
or right of the width-wise centerline P1 of the cartridge
inserting/ejecting opening 253, as shown in FIG. 24 or 25. At this time,
the disc cartridge 201 may be corrected in its orientation by rotating it
in a direction causing the coincidence of the centerlines P1 and
P2, in the course of the insertion thereof through the cartridge
inserting/ejecting opening 253, with the portion of the arcuate section
7, abutting against one of the lateral sides of the cartridge
inserting/ejecting opening 253, as the center of rotation, as shown in
FIG. 26. Thus, the disc cartridge 1, according to the present invention,
may reliably be inserted into the cartridge holder 254, even in case the
inserting direction thereof through the cartridge inserting/ejecting
opening 253 is inclined significantly.

[0167]The disc cartridge 201, inserted into the cartridge holder 254, is
further introduced into the cartridge holder 254, whereby the shutter
unit 215 is moved relative to the main body unit of the apparatus 251 to
open the aperture for the head part 13. That is, when the disc cartridge
201 has been introduced halfway in the cartridge holder 254, as shown in
FIG. 27, a portion of a shutter unit movement inhibit spring 62, formed
by segmenting a part of the sidewall section of an L-shaped cartridge
retention part 261 in one lateral side of the cartridge holder 254,
intrudes into the window 233 formed in the connecting piece 221 of the
shutter unit 215, thereby thrusting the thrust part 230 to cause rotation
of the lock lever 228 in the direction indicated by arrow D in FIG. 19,
as described previously. When rotated in the direction indicated by arrow
D in FIG. 19, the lock lever 228 is disengaged from the mating engaging
part 229 of the engagement piece 231 to release the lock of the shutter
unit 215 with respect to the main cartridge body unit 5. When unlocked
from the main cartridge body unit 5, the shutter unit 215 is movable
relative to the main cartridge body unit 5.

[0168]The cartridge holder 254, on which is loaded the disc cartridge 1
according to the present invention, is further provided with a shutter
releasing piece 63. This shutter releasing piece 63 intrudes into a guide
groove 49, formed in the lateral surface 8 of the main cartridge body
unit 5, until it abuts against the lateral side of the shutter unit 215.

[0169]When inserted into the inside of the cartridge holder 254, until
unlocking of the shutter unit 215, the shutter releasing piece 263 abuts
against the lateral side of the shutter unit 215, to inhibit the movement
of the shutter unit 215 relative to the main cartridge body unit 5, as
shown in FIG. 27. When the disc cartridge 1 further intrudes from the
position shown in FIG. 27 towards the inner part of the cartridge holder
254, in the direction indicated by arrow E, the main cartridge body unit
5 is moved along the direction as indicated by arrow E, thereby opening
the aperture for the head part 13, as shown in FIG. 28.

[0170]If, as the movement of the shutter unit 215 is inhibited, the disc
cartridge 201 is moved in the direction indicated by arrow E in FIG. 27,
with the main cartridge body unit 5 then opening the aperture for the
head part 13, the torsion coil spring 239, forming the shutter
opening/closure unit 238, is biased, as described above with reference to
FIGS. 19 and 20. When the main cartridge body unit 5 is moved in the
direction indicated by arrow E in FIG. 27, such that the coil part 239c
surpasses the location of the support pin 242, lying along the direction
of movement of the shutter unit 215, thus biasing the torsion coil spring
39, the biasing direction of the torsion coil spring 239 is reversed. The
shutter unit 215 is then moved in the direction of arrow F in FIG. 27,
opposite to the direction of movement of the main cartridge body unit 5,
thus opening the aperture for the head part 13, as shown in FIGS. 11, 21
and 28. At this time, the shutter unit 215 is biased by the torsion coil
spring 239 for opening the aperture for the head part 13, thus reliably
retaining the aperture for the head part 13 in the opened state.

[0171]The disc cartridge 201, inserted into the cartridge holder 254, with
the aperture for the head part 13 opened by the above-described
operation, is loaded in position on the cartridge loading section,
provided in the disc driving device 250. At this time, the optical disc 2
is loaded in position in a disc driving unit. This disc driving unit is
then actuated to reproduce the program data recorded on the optical disc
2 to run the program.

[0172]For ejecting the disc cartridge 1, loaded on the disc driving device
250, after reproducing the optical disc 2, an ejection button 255 is
pressed. On pressing the ejection button 255, the disc cartridge 1,
loaded on the cartridge loading section, is ejected. After the ejection
operation is carried out, the shutter unit 215 is moved relative to the
main cartridge body unit 5 to revert to the initial position of closing
the aperture for the head part 13 to lock the shutter unit 215 in this
position of closing the aperture for the head part 13, by the reverse of
the operation, described above. By this operation of restoring the
shutter unit 215 to the closure position, the disc cartridge is ejected
via the cartridge loading/unloading opening 253, so that the ejection of
the disc cartridge 201, loaded on the disc driving device 250, comes to a
close.

[0173]The state in which the disc cartridge 201 according to the present
invention is loaded on the disc drive device 250 is further explained.
The disc cartridge 201 is loaded on the cartridge loading section 67,
provided in the main cartridge body unit 51, with the lower surface
thereof as a loading surface, as shown in FIG. 29. In this lower surface
of the disc cartridge, there is formed a disc driving opening 12 in which
is inserted a turntable 66 forming the disc rotating driving unit 65
provided in the disc drive device 250.

[0174]Meanwhile, the cartridge loading section 67 is mounted on a base 69
carrying a disc rotating driving unit 65 and an optical pickup 68 for
reproducing the data recorded on the optical disc 2. The cartridge
loading section 67 is provided with a positioning pin 70 for positioning
the disc cartridge 1 in the planar direction and a positioning lug, not
shown, for positioning the disc cartridge 201 in the height-wise
direction. The disc cartridge 201 is loaded on the cartridge loading
section 67, as it is positioned in the planar and height-wise directions,
by the positioning pin 70 engaging in each of the first and second
positioning holes 43, 44 and by the lower surface being supported by the
height positioning lug.

[0175]With the disc cartridge 201 of the present invention, the portion
facing the aperture for the head part 13 of the upstanding peripheral
wall section 4a of the lower cartridge half 4 is formed with the cut-out
25 and thereby opened.

[0176]At least the portion facing the aperture for the head part 13 of the
slide guide 18 carrying the shutter unit 215 provided to the upper
cartridge half 3 is of a height H1 not protruding from the lower
surface 2a of the optical disc 2 facing the lower cartridge half 4, as
shown in FIG. 24, when the optical disc 2 in the disc cartridge 201,
loaded in position in the height-wise direction on the cartridge loading
section 67 has been loaded in position on the turntable 66.

[0177]The disc cartridge 201, constructed as described above, is able not
only to locate an entire optical pickup 68, as a head part for reading
out information signals, recorded on the optical disc, within the main
cartridge body unit 5, as shown in FIG. 29, when the shutter unit 215 has
been moved to open the aperture for the head part 13, but also to locate
the components of the optical block 72, other than an objective lens 71,
condensing the light beam, scanning the signal recording area of the
optical disc 2, outwardly of the main cartridge body unit 5, as the
objective lens 71 is located within the main cartridge body unit 5, as
shown in FIG. 20, when the optical pickup 68 has been moved to a position
scanning the outer rim of the optical disc 2.

[0178]As a result, with the disc cartridge 201, according to the present
invention, the optical pickup 68 may be located at an optional position
across the inner and outer rims of the main cartridge body unit 5, as the
optical pickup is kept in proximity to the optical disc 2, and hence the
signal recording area may be provided up to the outer rim of the optical
disc 2, thus increasing the recording capacity of the optical disc 2.
Moreover, since the optical pickup 68 may be located in proximity to the
optical disc 2, the numerical aperture NA of the objective lens 71 may be
increased, and hence the beam spot of the light beam condensed on the
signal recording area of the optical disc 2 may be reduced, thereby
improving the recording density of the information signals recorded on
the optical disc 2. In addition, since the recording density may be
improved with increase in the recording capacity, the optical disc 2 of a
preset recording capacity may be reduced in size. The optical disc 2 may
be scanned as the optical pickup 68 is located at an optional position
across the inner and outer rims of the main cartridge body unit 5, the
main cartridge body unit 5 and hence the recording and/or reproducing
apparatus employing the disc cartridge 201 may be reduced in size.

[0179]The disc cartridge 201, described above, includes the shutter unit
215 for closing the aperture for the head part 13. However, the disc
cartridge according to the present invention may also be devoid of the
shutter member, with the aperture for the head part being then opened.
With this disc cartridge, the portion of the upstanding peripheral wall
section of the lower cartridge half, lying opposite to the aperture for
the head part, is opened by being formed with the cut-out 25. That is,
the portion of the aperture for the head part, extending from the inner
rim up to the outer rim of the main cartridge body unit 5, is opened. The
portion of the upstanding peripheral wall section, facing the entrance
aperture for the head part, is also cut out.

[0180]When the present disc cartridge is loaded in position along the
height-wise direction on the cartridge loading section in the disc
recording and/or reproducing apparatus, the portion of the upper
cartridge half facing the aperture for the head part and the entrance
aperture for the head part is of a height H1 not protruding from the
lower surface 2a facing the lower cartridge half 4 of the optical disc 2,
as in the case of the disc cartridge 201.

[0181]With this disc cartridge, the optical pickup may be positioned
across the inner and outer sides of the main cartridge body unit, as the
optical pickup is close to the optical disc, so that the signal recording
area may be formed up to the outer rim of the optical disc, thereby
increasing the recording capacity of the optical disc.

[0182]Although the disc cartridge having housed therein the replay-only
optical disc has been explained in the foregoing, the present invention
may similarly be applied to a recording and/or reproducing optical disc
adapted for re-recording the information signals, or other types of the
recording mediums, with comparable merits.

INDUSTRIAL UTILIZABILITY

[0183]Since the disc cartridge according to the present invention may be
reduced in size, it may be used with advantage as a recording medium for
a recording and/or reproducing apparatus reduced in size for portable
use.

[0184]It should be understood that various changes and modifications to
the presently preferred embodiments described herein will be apparent to
those skilled in the art. Such changes and modifications can be made
without departing from the spirit and scope of the present subject matter
and without diminishing its intended advantages. It is therefore intended
that such changes and modifications be covered by the appended claims.